Index Contour Interval

A contour line proven on a map in a distinct manner for ease of identification, being printed extra closely than different contour strains and normally labeled with a price (such as parent of elevation) alongside its course. It seems at ordinary intervals, such as each fifth or from time to time each fourth contour line (depending on the contour interval).

Computation Of Intervals

The computation of the contour intervals is as below,

Step 1:-First of all, detect two index contour traces that are named with a specific elevation.

Step 2:-Now compute the difference between the two chosen index contour strains installed from a map. To attain the difference, subtract the greater expanded line from the decrease multiplied line reading.

Step 3:-Directly count number the range of non-index line contour strains between the two index contour strains unique for the contour interval computing in the 1st step.

Step 4:-The range of traces received in the above step is received and delivered with 1. For Example: If the wide variety of strains between two index traces is 5. Then add 1 to 5 which turns into 6.

Step 5:-The final step is the quotient of the distinction between two index traces (step 2) and the quantity of strains between two index traces plus 1 (step 5).

Step 6:-The remaining reply we get after dividing is the contour interval of the precise topographical map.

Rules of Contour Intervals

  • Every factor of a contour line has a comparable elevation.
  • Contour traces wonderful uphill from downhill.
  • Contour traces in no way contact or move every different than at a cliff.
  • Every fifth contour line is darker in shade than different contour lines. This is an INDEX contour line.
  • Contour strains are nearer collectively in steep terrain and farther aside in flat areas.

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What Is Contour Interval?

Contour interval is an essential thinking in cartography, geography, and topography. It refers to the vertical distance or distinction in elevation between two successive contour strains on a map or a topographic profile.

Contour traces are imaginary strains on a map that join factors of equal elevation and furnish a two-dimensional illustration of the third-dimensional terrain.

The contour interval is normally expressed in devices of dimension such as feet, meters, or gadgets of elevation relative to sea level. The contour interval is decided with the aid of the scale of the map and the diploma of alleviation of the terrain being represented.

On large-scale maps with a lot of topographical detail, the contour interval is generally smaller, whilst on small-scale maps with much less detail, the contour interval is larger.

How To Calculate Contour Interval On Maps?

A map legend typically specifies the contour interval on the map, however once in a while simply a component of a map is available. Understanding how to compute the interval will become a treasured skill.

On most of the maps, every fifth contour line, indicated as a heavier or darker line, is an index line or index contour.

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Uses Of Contour Maps

  • You can pick a appropriate web site for your development activity.
  • You can decide the reservoir capacity.
  • Alignment of roads, canals and transmission strains is carried out correctly thru contour lines.
  • The traits of the floor can be determined.
  • Earthwork quantity estimation.
  • Ground traits (e.g. flatness, uniformity, sloping, undulations or hills, etc.)
  • Using the contour map, you can pick out the most appropriate and low-cost web site for your work, such as roads, railroads, canals, pipelines, dams, and reservoirs.
  • The quantity of reservoir storage water, cuts and embankments can be estimated the use of contour lines.
  • You can use contour traces to graph navy operations.
  • They are used to attain statistics used in the diagram and building of irrigation constructions such as dams.

How to Find Contour Interval?

The calculation of the contour interval,

  • Considering the above map for the calculation of intervals, the steps worried in contour interval computation.
  • Let’s count on two index contour lines, 7000 and 7100, and compute the interval between them.
  • The distinction between the two chosen index contour traces 7100 and 7000 is 7100 – 7000 = 100
  • Now depend the wide variety of non-index strains contour strains between 7000 and 7100 as 4.
  • The wide variety of strains obtained in the above step is four and introduced with 1.
  • Adding, four + 1 = 5
  • Now divide one hundred via 5, 100/5 = 20 gadgets

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